Perhaps only readers of marine mammal biologist Victor Scheffer (The Year of the Seal, Adventures of a Zoologist) can quite appreciate what Scott and Sweet have accomplished, this time, in recording the extraordinary mass-breeding of the Pribilof seal herd: ""the largest assemblage of wild animals in any one place today."" First to clamber up the rocks are the giant bulls, come to stake out their territories and wait for the females' arrival in June; ""suddenly, out of the sea, the cows are there, returning to the place of their birth, landing on the beach in wave after wave of silvery-brown. As soon as they touch the shore the eager beachmasters begin collecting them."" Many of the females are pregnant and about to give birth--their wombs have two branches, we learn: ""About one week after the first pup is born, they are able to conceive the next year's pup in the 'resting branch.'"" So the mating and the nursing go on together, in a chaos of bodies and a clamor of sounds ""and tender moments of wooing."" For the duration of the breeding season, up to two months, the beachmasters neither eat nor drink, and hardly sleep (getting visibly haggard, and fagged-out); meanwhile, ""the pups are in full motion, bleating, rollicking, swarming into the water to polish their swimming technique. . . ."" Complete with fur-seal traits, the conservation situation, and brief word of ""the unusual family called marine mammals"": dramatic and measured. Copyright ©Kirkus Reviews, used with permission.